The present invention relates to a new and improved construction of a conveyor apparatus, especially for printed products.
Generally speaking, the article conveying apparatus of the present development is of the type comprising gripper clamps anchored in spaced relationship from one another at a revolving traction or tension element. The one movable clamp portion is brought into a closed position by means of an actuation element which coacts with a stationary control device and it is retained in such closed position by a releasable locking device.
With such type prior art conveyor apparatus the movable clamp portion is attached to a guide bolt which is displaceably guided in its axial direction within the gripper housing against the action of a compression or pressure spring. Significant in this regard is German Patent Publication No. 2,519,561 and U.S. Pat. No. 3,955,667. In the closed position the guide bolt, and thus, the movable clamp portion is locked by means of a releasable clamp lock which bears against the guide bolt and arrests the same. The closed position of the movable clamp or clamping portion is not exactly defined and depends upon the thickness of the seized product. To render possible a faultless grasping of products of any random thickness, both of the clamp portions must possess an appropriately long length. This results in the lever arm of the closing force acting upon the guide bolt becoming correspondingly longer. This leads, in turn, to the fact that the guide bolt can cant, something which impairs both the proper closing operation and also an immediate opening of the gripper. A faultless clamping of the seized products and a faultless opening at the desired site therefore is not ensured for with such construction. Additionally, the closed position which is governed by the thickness of the seized product does not satisfactorily take into account the requirement that thicker products, because of their usually greater weight, must be retained with a larger clamping force than thin products.